1. Field of the Invention
The present invention relates to an on-vehicle display apparatus installed in an automobile for displaying TV programs, map information of a navigation system, and the like, and more specifically, to an on-vehicle display apparatus having a display main body that can be retracted when not in use.
2. Description of the Related Art
When this type of on-vehicle display apparatus is in use, the display main body can be raised to a position where the display main body can be easily viewed by the user. When the apparatus is not in use, the display main body can be retracted, for example, in the dashboard. Thus, the display main body not in use does not take up space in the car.
In recent years, on-vehicle display apparatuses in which a display main body is moved between a retracted state and a raised state by the drive force of a motor have become common. When the display main body is in a predetermined retracted position, the display main body is moved forward and raised by transmitting the rotational drive force of the motor through a power transmission mechanism including gears and levers to the display main body. When retracting the display main body in the raised state, the display main body is inclined and moved backward to the retracted position by transmitting the rotational drive force of the motor in the reverse direction through the power transmission mechanism to the display main body.
In conventional on-vehicle display apparatuses using the drive force of a motor, usually, a power transmission mechanism is configured by combining many gears with levers or racks, and brace-like rotating arms (supporting arms) are attached to both left and right sides of a display main body. For this reason, this type of on-vehicle display apparatus has a problem given that the configuration of the power transmission mechanism is complex, the number of components is large, and it is difficult to reduce the size and thickness of the apparatus.
In a conventional on-vehicle display apparatus described in U.S. Patent Application Publication No. 2010/0226086, a second lever is rotatably connected to the distal end of a first lever rotationally driven by the drive force of a motor, a guide portion extending from the lower end of the back of a display main body is rotatably connected to the distal end of the second lever, and thus the display main body rises obliquely upward as the first lever is rotated forward. Thus, such a conventional on-vehicle display apparatus need not use many gears in a power transmission mechanism that moves the display main body, and is relatively simple in configuration.
However, in the conventional on-vehicle display apparatus described in U.S. Patent Application Publication No. 2010/0226086, the display main body is pulled obliquely downward and is thereby retracted, and a space for the rotation of the first and second levers and guide portion that rotate in a vertical plane needs to be secured. Thus, the thickness of the whole apparatus cannot be reduced significantly.
In this type of on-vehicle display apparatus, when the display main body has been raised or when the display main body is being raised, sometimes an external force that tries to forcibly retract the display main body or an external force that interferes with the raising of the display main body is applied owing to collision with the user's body, mischief of a child, or the like. In that case, there is a possibility that gears that constitute the power transmission mechanism of the on-vehicle display apparatus are subjected to an excessive force and damaged. There is known an on-vehicle display apparatus in which, in order to avoid such a possibility, a clutch mechanism is interposed in the power transmission pathway. However, adding a clutch mechanism makes the structure larger, and thus makes it difficult to reduce the whole apparatus in thickness. When the transmission pathway of an unwanted external force applied to the display main body is blocked by a clutch mechanism, there is a possibility that the clutch plate or the like slides and generates a rasping abnormal noise.